Cartridge feed mechanism for a firearm

ABSTRACT

THE BREECHCASE OF THE FIREARM HAS TWO LARGE SIDES WITH OPENINGS FOR THE CARTRIDGES COMING ALTERNATELY FROM TWO FEED MECHANISMS ON OPPOSITE SIDES OF THE BREECHCASE. A SINGLE MOTOR MEMBER IN THE FORM OF A FORK CONNECTED TO THE RECOILING PART OF THE FIREARM RECIPROCATES LONGITUDINALLY AND IS OF SUCH SHAPE AND POSITION THAT IT DRIVES AT ONE TIME ONLY THE DRIVING MEMBER OF THAT FEED MECHANISM WHICH IS IN FIRING POSITION.

Nov. 2, 1971 B. MAILLARD CARTRIDGE FEED MECHANISM FOR A FIREARM Original Filed April l. 1968 3 Sheets-Sheet l Nov. 2, 1971 B. MAILLARD CARTRIDGE FEED MECHANISM FOR A FIREARM I5 Sheets-Sheet 2 Original Filed April l. 1968.

B. MAILLARD CARTRIDGE FEED HECHANISM FOR A FIREARM Original Filed April 1. 1968 Nov. 2, 17971 3 Sheets-Sheet I5 United States Patent O 3,616,724 CARTRIDGE FEED MECHANISM FOR A FIREARM Bernard Maillard, Geneva, Switzerland, assignor to' Brevets Aero-Mecaniques S.A., Geneva, Switzerland Original application Apr. 1, 1968, Ser. No. 714,524, now

Patent No. 3,447,418, dated .lune 3, 1969. Divided and this application Oct. 21, 1968, Ser. No. 810,861 Claims priority, application iilxembourg, July 31, 1967,

s4, o Int. Cl. F41d 9/02 U.S. Cl. 89-33 SF 7 Claims ABSTRACT OF THE DISCLOSURE This application is a division of my previous application Ser. No. 714,524, filed Apr. 1, 1968, now Pat. No. 3,447,418, issued June 3, 1969.

The present invention relates to firearms that are at least se-mi-automatic, in particular to automatic firearms of calibre advantageously comprised between 2O and 50 mm. Firearms of these types recock themselves automatically after each round, and the firing of the following round can either require an action on the part of the gunner (semi-automatic fire-arms) or not (automatic firearms).

The invention comprises principally the following features, taken separately or in any combination.

According to a first feature of the invention, a fire-arm comprises a substantially cylindrical breech mechanism adapted to be displaced in an alternating translatory movement in a breechcase having towards the rear an interior shape and an exterior shape which are substantially rectangular, this breechcase having in one of the small sides of its substantially rectangular cross-section an ejection passage for the ejection of the empty cartridge cases and in the two large sides of said cross-section introduction openings for the introduction of cartridges coming respectively from two feed mechanisms which can be alternately put in firing position, a helical counter-recoil spring being provided between the breech mechanism and the rear part of the breechcase, the lire-arm being characterized by the fact that the part of the breechcase which is of substantially rectangular cross-section, has at the level of the cartridge introduction openings, four guiding surfaces for guiding the 4breech mechanism as well as for guiding the counter-recoil spring whose exterior diameter is substantially equal to the exterior diameter of the breech mechanism, said guiding surfaces being situated on a common geometrical cylinder of revolution about an axis having the same direction as the axis of the barrel of the lire-arm.

According to a second feature of the invention, a firearm is adapted to receive two feed mechanisms articulated on opposite sides of the breechcase of the tire-arm and controlled so that one of them is in firing position when the other is out of firing position and vice-versa, each feed mechanism having a mechanism for advancing cartridges and for transmitting motion housed in the feed mechanism and a driving member adapted to be displaced in a direction substantially parallel to the axis of the` barrel of the fire-arm, the lire-arm being characterized by the fact that it comprises for the two feed mechanisms a single motor member having alternating longitudinal motion connected Cce to a recoiling part of the lire-arm and of form and position such that it meets, during its recoil motion, only the driving member of the feed mechanism that is in firing position.

According to a third feature of the invention, a fire-arm comprises at the interior of a breechcase, on the one hand, a sleeve to which the barrel of the fire-arm is fixed `in a removable manner by a bayonet joint, and on the other hand, a nut Which is screwed on the front of the breechcase and which serves for maintaining the sleeve in longitudinal direction towards the front and in transverse direction at the same time, connecting means being provided between the part of the barrel and/or the sleeve situated at the front of the nut .and a zone situated at the rear of the sleeve between the sleeve and the breechcase, more particularly, the sleeve of this tire-arm being adapted to recoil with the barrel with respect to the breechcase and being guided in translation by said nut, the fire-arm being characterized by the fact that the sleeve has two successive collars, namely a front collar Whose diameter is equal to the interior diameter of the nut and which is disposed at the interior of this nut for maintaining the sleeve transversely with respect to the nut, and a rear collar whose diameter, which is greater than the diameter of the front collar, is equal to the interior diameter of the breechcase and which is disposed behind the nut for maintaining the sleeve longitudinally with respect to the nut and transversely with respect to the breechcase, and by the fact that the interior diameter of the nut is sufficiently large so that an intermediate element of said connecting means passes through the front collar without touching the nut, due to which it is possible to unscrew or screw the nut for dismantling or remantling the sleeve, without preliminary dismantling of the connecting means.

According to a Ifourth feature of the invention, a firearm has an ejection system comprising an extractor carried by the movable breech mechanism, and diametrically opposed, an ejector carried by the breechcase and comprising at the front a transverse striking surface for the rear edge of the cartridge case to be ejected, which ejector is controlled by the breech mechanism in a manner to present said striking surface in the trajectory of this rear edge during the recoil of the breech mechanism, the fire-arm being characterized by the fact that the ejector comprises, at the front of this striking surface, a projection adapted to strike transversely the lateral surface of the cartridge case, before the impact with the rear edge, in a manner to tip the cartridge case before this impact in the direction of the ejection passage, which attenuates the violence of said impact.

The present invention will be clearly understood from the following specific description of a preferred embodiment of the invention, given, merely by way of example, with reference to the accompanying drawings, in which:

FIGS. 1 and 2 (both divided by a verticalbroken line into two parts a and b intended to be considered end to end) show a fire-arm according to the present invention, respectively in vertiral section and in horizontal section along lI-II of FIG. 1;

FIGS. 3 and 4 are sections along the lines III and IV respectively of FIG. 1; and

FIG. 5 illustrates the operation of the ejection system visible in FIG. 1.

The tire-arm shown in the drawings is a heavy machine gun of calibre between 20 and 30 mm., for example.

Withregard to the fire-arm as a whole, it comprises a substantially cylindrical breech mechanism 1 adapted to be displaced in a translatory movement in a breechcase 2 having towards the rear an interior shape and an exterior shape which are substantially rectangular (see FIG. 4), the small sides of this cross-section being designated by 3 and 4 andthe large sides by 5 and 6. The breechcase 2 has, on the small side 3, an ejection passage 7 for the empty cartridge cases, and on the two large sides and 6, introduction openings 8 for the introduction of cartridges corning from two feed mechanisms 9, on opposite sides of the breechcase 2, which can be alternately put into position for firing. A helical counter-recoil spring 10 is provided between the breech mechanism 1 and the rear part of the breechcase A2.

With regard to the breech mechanism 1, it is advantageously constructed according to the U.S. patent application filed on even date herewith by the present applicant for Breech mechanism for automatic or semiautomatic arms, now Pat. No. 3,507,187, issued Apr. 2l, 1970. Such a breech mechanism 1 comprises a breechblock 11 which is locked by rotation and which comprises on the one hand, at its front part, a cup-shaped recess 12 in which the rear ends (not shown) of the cartridges to be fired come into engagement, and on the other hand, exteriorly, locking lugs 13 which co-operate with lugs 14 formed on a sleeve 15, which receives the barrel 16 in a removable manner due to a bayonet joint 17. The breech mechanism 1 also comprises a casing 18, formed of two casing elements in the form of shells separated approximately by the plane of FIG. l. The casing 18 can slide without rotatnig in the breechcase 2 and is disposed around the breechblock 11. This breechblock passes through the casing 18 at the rear in a manner to cooperate with the usual breech damping device 19, situated at the rear of the breechcase 2. A spindle 20 passes through the breechblock 11 and is connected, in the interior of this breechblock, to the firing pin 21 and, at the exterior of this breechblock, without play, to the casing 18. The lugs 13 of the breechblock 11 are situated on the same cylinder of revolution as a part at least of the exterior surface of the casing 18, which permits the breechblock 11 to be guided by the contact of the casing 18 and of at least some of its lugs 13 with the same surface (which will be more explicitely described hereafter). A spring 111 acting on the firing pin 21 tends to push the unit formed by the firing pin 21 and the casing 18 towards the front of the breechblock 11.

In order to transform into a rotary move-ment of the breechblock 11, the translatory movement which is produced between the casing 18 and this breechblock when the breechblock arrives substantially at the position of closing shown in FIGS. l and 2, the spindle 20 carries two cylindrical rollers 22 (FIG. 4) co-operating respectively with skews 22a formed in a cylindrical enlarged portion 23 of the breechblock 11.

At its exterior surface, the casing 18 carries two longitudinal projections 24 and 25 whose longitudinal lateral faces 24a and 25a co-operate with the interior faces of the large sides 5 and 6 of the breechcase 2 (see FIG. 4) to prevent the casing from turning at the interior of this breechcase. The projection 24 comprises a front face 24b adapted to co-operate with a sear 26 for stopping the breech mechanism in the open position. The projection 25 comprises a front face 25b adapted to co-operate, on the one hand, with an unlocking push-piece 27 (actuated in the manner described hereafter by tapping the gases in the barrel 16) which is provided for unlocking the breech mechanism 1 with respect to the breechcase 2, and on the other hand with arecocking device which permits the breechblock 11 to be brought back towards the rear after the breechblock has been stopped in the closing position. Such a recocking device can comprise a chain 28, one link of which carries a hook for the face 25b. The chain 28 is stretched between =a front idler pinion 29 and a rear pinion 30 fixed on a spindle 31 rigid with a crank 32. The projection 25 further co-operates by the rear with an ejector 33, mounted on a transverse spindle 34, for the purpose of making it tip, the projection 25 having a longitudinal groove 25C lfor the passage of the ejector.

Between two of its lugs 13, the breechblock 11 carries 4 an extractor 35, and on the diametrically opposed side, it has .a groove 36, for the passage of the ejector 33, which leads into the cup-shaped recess 12. The extractor can be maintained in place by a leaf-spring 37.

To maintain the casing 18 imperatively in its extreme rear position with respect to the -breechblock 11 during the reciprocating movement of the breech mechanism 1 inside the breechblock 2, a leaf-spring 38, carried by the breechblock 11, tends to project by its rear part against a bearing face 39 of the casing 18. An inclined surface 40, carried by the breechcase 42, can retract the leaf-spring 38 by acting on a push-piece 41 passing through the casing 18.

That being the case, according to -a first feature of the invention, the part 3-6 of the breechcase 2 that is of substantially rectangular cross-section has, at the lefvel of the cartridge introduction openings 8, four guiding surfaces 42 for the breech mechanism 1 (casing 18 and lugs 13) as ,well as for the counter-recoil spring 10 whose exterior diameter is substantially equal to the diameter D of the breech mechanism, these guiding surfaces 42 being situated on a cylinder of revolution about an axis parallel to the axis X-X of the fbarrel 16 and generally coincident with this axis X-X. The trace of this cylinder on the plane of FIG. 4 is coincident with the exterior contour of the casing 18 which is also the exterior contour of the spring 10.

According to an advantageous embodiment of this feature of the invention, the part of substantially rectangular cross-section 3-6 of the breechcase 2 is extended towards the front by a part 43 whose interior and exterior crosssections are cylinders of revoltion about the axis X-X of the barrel 16; the part 43 receives the sleeves 15 to which the barrel 16 is xed in a removable manner; the annular space left free between the exterior of the sleeve 15 and the interior of the cylindrical part 43 of the breechcase 2 houses the control devices of the feed mechanism or mechanisms 9 (which control devices will be described hereafter), the damping devices for the recoil and the return to firing position and the breech mechanism unlocking device with its push-piece 27.

The passage 7 and the openings 8 extend towards the front to the front end of the sides 3, 5 and 6.'The small side 4 is approximately tangential to the cylindrical part 43. This part and the elements of each large side 5 and 6 that exist on both sides (in the transverse direction) of the openings 8 are connected among themselves by transverse partitions 6-1 that render the breechcase 2 rigid and assure its fluid-tightness.

It is supposed in the following that the breechcase 2 is fixed and that the unit formed by the sleeve 15 and the barrel 16 can recoil with respect to this breechcase at the interior of which it is guided. The damping devices for the recoil and for the return to firing position can be of two types, mechanical and hydraulic. The mechanical damping devices, which are five in number in the embodiment represented, each comprise a helical spring 44, coiled around a telescopic guide 45 parallel to the axis X-X of the barrel 16, which bears, at the front, against a collar 46 integral with the sleeve 15, and at the rear, against a ring 47 rigid with the breechcase 2. This ring 47 can be maintained against a shoulder 48 of the breechcase not only by the springs 44 but also by rods 49 fixed by one end to this ring, passing freely through the collar 46 and bearing by the other end on a nut 50 screwed on the front of the breechcase 2. The hydraulic damping devices, which are two in number in the embodiment represented, comprise oil dash-pots each comprising a cylinder 51 coupled to the ring 47 and a piston whose piston-rod 52 is coupled to the collar 46, although of course the pistons and cylinders can be interchanged.

The unlocking device, with its push-piece 27, for the vbreech mechanism 1 can comprise a cylinder 53, backed onto the collar 46, and a piston or plunger 54 rigid with the push-piece 27. The cylinder 53 is connected by a conduit 55, comprising'a throttle device 56 (that is to say a body traversed by a channel Whose cross-section permits the regulation of the operation of the device by constriction of the gases), to a zone of the barrel 16 situated at a certain distance from the cartridge chamber 57. The unit formed by the push-piece 27 and the piston or plunger 54 is returned towards the front by a spring 58, the push-piece 27 and this spring passing through the ring 47 through an opening visible at the bottom of FIG. 1.

In the annular space left free between the exterior of the sleeve 15 and the interior of the cylindrical part 43, the damping devices for the recoil and for the return to firing position and the unlocking device for the breech mechanism 1 can occupy the lower sector, as shown in FIG. 3, the unlocking device being advantageously placed in a manner to separate these damping devices into two approximately symmetrical groups. In the space in question, a guiding key 59 can be disposed, rivetted to the breechcase 2, ad lying without play in grooves which pass through the collar 46 and the ring 47 parallel to the axis X-X thus preventing them from rotating about this axis. In particular, it will be understood that at the firing of a round, the starting of the rotation of the projectile, by penetration of the helical lands of the barrel 16 into the driving-band of the projectile, generates, by reaction, in the unit formed by the barrel and the sleeve 15, a torque which is absorbed by the key 59, which prevents this unit from rotating in the interior of the breechcase 2.

To the rear of the introduction openings 8, the large sides and `6 of the part of substantially rectangular crosssection of the breechcase 2 are closed by co-axial curved parts -60 whose interior diameter is equal to the diameter D of the breech mechanism 1 and which are adapted to render the breechcase 2 fluidtight and rigid, while guiding the breech mechanism 1 and the counter-recoil spring 10. In FIG. 4, the central zone of the curved parts 60 can be seen through an opening 62 in the transverse partitions 61, the interior contour of these parts 60 being coincident with the exterior countour of the casing 18 (which is also the exterior contour of the spring The interior width indicated by the arrow a, between the large sides 5 and 6, is larger than the maximum diameter of the cartridge cases (so that these cartridge cases can pass through the passage 7) and smaller than, but as near as possible to the diameter D of the breech mechanism (to permit the curved parts to be fitted in place).

The curved parts 60 are extended at the rear, beyond the part of substantially rectangular section 3-6, by two cylindrical sectors 63 provided with bayonet lugs 64 and adapted to receive a closing block 65 which serves as a support for the counter-recoil spring 10 and contains the damping device 19 of the breech mechanism. In addition to a cylindrical part 65a which fits partially on the sector 63, and a back which is comprised by an element of the device 19, the block 65 comprises at the front two radial wings 65b adapted to block off the zones of the part of substantially rectangular cross-section 3-6 which are not covered by the cylindrical part 65a.

Inside of the part of substantially rectangular crosssection of the breechcase 2 and in the neighbourhood of the small sides 3 and 4 of this cross-section, there can be disposed, at the exterior of the volume swept by the breech mechanism 1, supplementary mechanisms such as the scar 26 and its damping spring 66, the ejector 33 and the recocking mechanism 28-30. A cam 67 serves to retract the sear 26 against the action of a spring 68.

It is advantageous to make the breechcase 2 carry externally, on one of the small sides of its substantially rectangular cross-section, for example on the side 4, at least one spindle or rod of articulation 69 for the alternate placing of the feed mechanisms 9 in tiring position, and on the other small side 3, the mechanism controlling the rotation of the feed mechanismsabout this rod 69.

With regard to the fastening and the control of the feed mechanisms 9, they are advantageously arranged as in my U.S. patent application Ser. No. 622,643 filed Mar. 13, 1967. For this purpose, the two feed mechanisms 9 are mounted in a manner that they can rotate about an axis Y--Y parallel to the axis X-X of the barrel 16. The axis of rotation Y-Y is materialized by a hinge 70 assembled by the rod 69. The mechanisms 9, which are in general belt feed mechanisms, are each provided with a cover 71 which can rotate about a hinge 72, with respect to a casing 82 fixed directly to the small side 4 of the breechcase 2, in order to permit the transverse introduction of the cartridge belt. Each cover is normally locked by a hook 73.

The mechanisms 9 are coupled by a fork 74 guided on the small side 3 in a manner that it can slide transversely with respect to the fire-arm. The fork 74 has slots 75 which each co-operate with a catch 76 rigid with the feed mechanism being considered. A slider 77, guided lon- Lgitudinally on the small side 3, actuates a lever 78 which is carried by a spindle 79 passing through the slider through an elongated slot. This lever has a curved head 78a, in the form of a dovetail, which is engaged in a mortise 74a of the fork 74. When the gunner displaces the slider 77 longitudinally in one direction or the other, it rocks the lever 78 about the spindle 79 and displaces the fork 74 transversely (toward the left of FIG. 4 if the position shown is the starting position), which puts out of action the feed mechanism 9 (atthe left of FIG. 4) which was in firing position, and puts in action the other feed mechanism, by rocking about the rod 69.

Each feed mechanism 9 has a mechanism for belt advancement and for motion transmission housed in the casing 82 of the feed mechanism and a driving member adapted to be displaced in a direction substantially parallel to the axis X-X of the barrel 16 of the fire-arm. According to the embodiment represented in FIG. 2, the bolt advancement mechanism comprises cartridge-pushing pawls 80 and the motion transmission mechanism for transmitting motion to these pawls is comprised by a lever 81 adapted to pivot about a spindle 83 and having a driving projection 84. The advancement mechanism can be of any type, for example as described in U.S. Pat. No. 3,198,075. Furthermore, the driving member of the feed mechanism is comprised by a roller 85 which is carried by one of the arms of a two-armed lever 86. The other arm of this lever carries a second roller 87 situated in the trajectory of the projection 84, the lever 86 pivoting about a spindle `88 parallel to the spindle 83. The arm of the lever 86 that carries the roller '8S is oriented in a manner such that this roller describes a circular arc practically identical with its tangent that is parallel to the axis X-X. It can be seen that, if the roller 85 is pushed towards the right of FIG. 2, it makes the lever 86 rock in the direction which raises the roller 87 with respect to the plane of FIG. 2, which makes the lever 81 rock in a manner such that its free end is displaced in the same direction. At least one spring (not shown) assures the return of the levers 81 and 86 by maintaining the roller 87 in contact with the projection 84.

For two such feed mechanisms, according to a second feature of the invention, the fire-arm comprises a single motor member having alternating longitudinal movement and connected to a recoiling part of the lire-arm, this motor member having a form and a position such that it meets, d-uring its active or recoil movement, only the driving member 85 of the feed mechanism 9 that is in firing position.

According to a particularly advantageous embodiment of this feature, the motor member has the form of a fork 89 whose base 89a is oriented towards the front and cooperates with longitudinal guiding surfaces and whose two branches 89b co-operate by their rear part respectively and alternately with the driving members or rollers y85 of the feed mechanisms. The fork 819 has a transverse 89C interconnecting the base 89a and the branches 89h. In each casing 82, a passage 90 i-s provided opposite the roller 85 for the corresponding branch 89b. It can be seen in FIG. 4 that the right feed mechanism, which is out of action, has its passage 90 out of the trajectory of the corresponding branch 89b, this branch passing freely into a notch 91 formed in the casing 82. On the contrary, the feed mechanism visible at the left of FIG. 4, which is in action, has its passage 90 just opposite the corresponding branch 89h, such that only this branch meets the roller 85 that is associated with it and can thus actuate the feed mechanism 9 that is in action.

It has been explained above that the control mechanisms of the feed mechanism or feed mechanisms 9 were placed, with other members, in the annular space left free between the exterior of the sleeve 15 and the interior of the cylindrical part 43 of the breechcase 2. These control mechanisms comprise essentially the fork 89, whose transverse 89e is curved to conform to the sector of the annular space that it occupies (see FIG. 3), as well as compression springs (with their guides) which are described hereunder.

As it has just been explained, the sleeve 15 essentially forms with the barrel 16 the recoiling part of the firearm whose breechcase 2 is fixed. The fork 89 is guided at the front by the collar 46 forming a part of the sleeve 15, due to a notch 92 through which the front end of the base 89a passes without appreciable lateral play. The front end of the base 89a can be maintained radially against the bottom of this notch by contact with the interior wall of the cylindrical part 43 of the breechcase 2, as can be seen at the top of FIG. 1. Furthermore the fork 89 is guided at the rear by a member fixed with respect to the breechcase 2, this member being advantageously comprised by the ring 47. For this purpose, this ring can comprise a bore 93 parallel to the axis X-X and adapted to guide an extension 89d of the base 89a, situated towards the rear beyond the transverse 89C. The ring 47 can furthermore comprise a central bore 98 for guiding the rear of the sleeve 15. The base 89a can carry a shoulder 89c5adapted to co-operate by abutment with the rear face of the collar 46 of the sleeve 15 Between the fork 89 and the collar 46 acts at least one compression spring adapted to make the fork recoil with respect to the breechcase 2, abutment means being pro- 'vided for bringing back the fork into tiring position during the forward return of the recoiling part 15, 16 of the fire-arm.

As can be seen in FIGS. 2 and 3, two compression springs 94, each wound around a telescopic guide 95 parallel to the axis X-X, can be disposed on both sides of the base 89a, these springs bearing at the rear against the transverse 89e of the fork.

The abutment means for bringing back the fork into tiring position comprise, preferably, a double shoulder 96 provided at the end of the base 89a, in front of the collar 46, and adapted to abut against the front face of this collar.

FIG. 3 shows that in front of this transverse the annular space dened hereabove receives the base 89a, four springs 94 with their guides 95, two hydraulic damping devices, 51 and 52, five mechanical damping devices 44 and 45, and the unlocking device 53 and 54 for the breech mechanism. To the rear of the transverse 89e, the springs 94 with their guides 95 are absent and the base 89a is replaced by the branches 89b and the extension 89d.

The interior of the base 89a of the fork can be in the form of a cylinder forming part of a dash-pot regulator for regulating the recoil speed of the fork, this recoil being accompanied by the relaxation of the springs 94. For this purpose, the base 89a is provided with a bore 97, parallel to the axis X-X, in which two pistons 99 and 100 can slide and are mounted one behind the other, with a certain axial play, on a rod 101. This rod passes in a liquid-tight marmer rearwardly through the bottom of the cylinder formed by the bore 97 and bears, preferably by the intermediary of the ring 47, against a stop 102 rigid with the breechcase 2. An annular se-aling ring 103, disposed in a slidable manner about the rod 101, is pushed by a spring 104 towards the two pistons 99 and 100, and the space situated in the bore 97 in front of the sealing ring 103 is filled with oil. It can be seen that the spring 104 has the effect of maintaining in this space a pressure sufficient to push the rod 101 into contact with the stop 102 and permits, moveover, the sealing ring 103 to be displaced to compensate for the variations of volume of this space which are due to the larger or smaller penetration of the rod 101. Between the front piston and the bore 97, play is provided which normally assures a constant speed of recoil of the fork 89 by passage of the oil from the front to the rear of this piston. The piston 99 carries elastic rings 105 which tend to separate the piston 100 from the piston 99. The piston 100 has channels 106 passing therethrough adapted to be blocked of; by the neighbouring face of the piston 99 when the pis- 'ton 99 is in contact with the piston 100. It can be sen that, if the speed of recoil of the fork 89 (towards the right of FIG. l) increases, the pressure prevailing in front (to the left) of the piston 100 increases and this piston compresses the rings 105 and comes into contact with the piston 99. This closes the channels 106 and the oil can only pass through the annular play provided at the periphery of the piston 100. The recoil of the fork 89 is thus well braked whereas its advance is not braked, in particular by reason of the semi-positive coupling between the rod 101 and the stop 102.

The lever 86 for motion transmission between the fork 89 and each feed mechanism 9, is housed in the casing 82 which is connected directly to the breechcase 2 whereas the lever 81 and the pawls 80, for the advance of the bolt, are housed in the cover 71. The spindle 88 of the lever 86 is thus xed to the casing 82 in which the passage 90 is formed, whereas the spindle 83 of the lever 81 is fixed to the cover 71. It will be understood that the coupling, by the projection 84 and the roller 87, between the two levers 86 and 81 permits opening and closing of the cover 71, for the transverse introduction of the cartridge bolt, without any particular precaution.

Advantageously, the breech mechanism is arranged in a manner such that the rear of the motor member or fork 89, in the rest position illustrated in FIG. 2, is located in front of the front face of the feed mechanisms. In other words, when the sleeve 15 is in its most forward position and when the shoulder 96 of the fork 89 is in abutment with the collar 46, the rear end of the one of the branches 89b that is located opposite a roller 85 does not penetrate into the corresponding passage 90. This permits the two feed mechanisms 9 to be rocked in the manner described above without the branches 89b of the fork 89 hindering this manoeuvre.

In the foregoing, a 4fire-arm has been described comprising in the interior of a breechcase 2, on the one hand, a sleeve 15 to which the barrel 16 of the fire-arm is fixed in a removable manner by a bayonet joint 17, and on the other hand, a nut 50 which is screwed on the front of the breechcase 2 and which serves to maintain the sleeve 15 in the longitudinal direction towards the front and in the transverse direction at the same time, connecting means 55 and 56 being provided between the part of the barrel 16 and/or the sleeve 15 situated at the front of the nut 50 and a zone situated at the rear of the sleeve 15 between this sleeve and the breechcase 2.

In this tire-arm, the sleeve 15 is adapted to recoil with the barrel 16 with respect to the breechcase 2 and is guided in translation by the nut 50.

According to a third feature of the invention which could, should the occasion arise, be used in fire-arms in which the breechcase 2 participates in the recoil and/or in which the connecting means are of another nature than a conduit for the gases, the sleeve 15 has two successive collars, namely a front collar 107, whose diameter is equal to the interior diameter of the nut 50 and which is disposed inside the nut for maintaining the sleeve 15 transversely (with sliding, according to the embodiment represented), and a rear collar whose diameter, greater than the diameter of the front collar 107, is equal to the interior diameter of the breechcase 2 and which is disposed to the rear of the nut 50 for maintaining the sleeve 15 longitudinally with respect to the nut 50 (by abutment) and transversely (with sliding) with respect to the breechcase 2. Preferably, this rear collar is the collar 46. Moreover, the interior diameter of the nut 50 is chosen sufficiently large (in other words, the radial thickness of this nut suiciently small) so that an intermediate element of the connecting means, and in particular the throttle device 56, passes through the front collar 107 without touching the nut 50.

The sleeve 15 is thus guided, at the front, by contact with the interior surfaces of the nut 50 (collar 107) and of the breechcase 2 (collar 46), and at the rear, by contact with the bore 98 of the ring 47. Its movement towards the front is limited by contact of the front face of its collar 46 with the rear face of the nut 50. A retractable locking device 108, having a ball or the like, prevents the nut from turning with respect to the breechcase 2.

Due to the arrangement of the nut 50 which'has just been described, it can be seen that it is possible to screw it or unscrew it, with a view to dismantling or re-assembling the sleeve 15, with preliminary dismantling of the connecting means and more particularly, according to the example shown, of the throttle device 56.

In the foregoing, an ejection system has been briey described which comprises an extractor 35 carried by the movable breech mechanism 1, and diametrically opposed, an ejector 33 carried by the breechcase 2 and actuated by the breech mechanism 1, by contact of the tail 33a of the ejector with the projection 25 of the breechblock 11.

More precisely, the ejector 33 comprises at the front a transverse striking surface 109 (FIGS. 1 and 5) for the rear edge of the empty cartridge case 110` to be ejected and it is controlled by the breech mechanism infthe usual manner such that it presents the striking surface 109 into the trajectory of this rear edge during the recoil of the breech mechanism. To simplify the drawings, the lugs 13 of the breechblock 11 have been omitted in FIG. 5.

According to a fourth feature of the invention, which can be applied whatever be the nature of the breech mechanism, and in particular, of its locking means (by rotation as described or with the aid of separate locks), the ejector 33 comprises, at the front of the striking surface 109, a projection 112 adapted to strike the lateral surface of the cartridge case 110 transversely, before the impact with the rear edge of the cartridge case. FIG. 5 shows the cartridge case 110 which, still maintained at the top by the extractor 35 after having been struck by the projection 112, has begun its tipping movement in the direction of the ejection passage 7. It is only then that the striking surface 109 hits the rear edge of the cartridge case, with a relative speed which is decreased by the forward speed imposed on the part of this edge that the surface 109 strikes. In this manner, the violence of the impact is decreased and the ejection trajectory is stabilized.

The operation of the tire-arm described above is the following.

When a cartridge is placed in :the chamber 57 and when the breech mechanism arrives in the position of FIGS. 1 and 2, the cartridge is fired, which causes the recoil of the unit formed by the barrel 16, the sleeve 15 and the breech mechanism 1. By the rear of the collar 46 of the sleeve 15, the recoil damping springs 44 and the control springs 94 of the feed mechanisms are compressed and the pistons of the recoil dampers 51 and 52 are driven towards the rear. The springs 94 drive the fork 89 towards the rear with a speed regularized by the dashpot 97 and 99-105, whatever be the resistance to the` traction of the belt in the one of the 'two feed mechanisms 9 that is in firing position. According to the stroke of recoil of the fire-arm, the collar 46 of the sleeve 15 abuts or does not abut against `the shoulder 89e of the fork 89. By the one of its branches 8911 which meets a roller 85, the fork makes the levers 86 and 81 of the feed mechanism in firing position pivot, which puts a cartridge in position for introduction.

When the bullet has passed the gas inlet of the conduit 55, the gases pass through the throttle device 56, penetrate into the unlocking cylinder 53 and act on the front face of the piston or plunger 54. This piston or plunger 54 compresses the spring 58 and drives the breech mechanism casing 18 in an accelerated movement. The casing 18, while recoiling, makes the breechblock 11 rotate in a manner such that it frees itself from the sleeve 15. The residual pressure of the gases in the chamber 57 contributes Ito make the breechblock 11 recoil, which it does while compressing the counter-recoil spring 10, the

-breechblock 11 finally abutting at the end of its stroke against the damping device 19. At the same time, the empty cartridge case is ejected in the manner described above.

The breech mechanism is then returned towards the front by the damping device 19 and the counter-recoil spring 10, drives the cartridge that was in position for introduction and introduces it into the chamber 57. The casing 18, which had been maintained at the rear of the breechblock 11 by the leaf-spring 38 during the reciprocation of the breech mechanism, is freed by the action of the inclined surface 40 and the spring 111 drives it towards the front, which, on the one hand, locks the breechblock 11 by making it rotate and then -brings the point of the firing pin 21 into the cup-shaped recess 12 (new percussion).

During the forward return of the breech mechanism, the springs 44 restore their energy while bringing back towards the front the sleeve 15 and the barrel 16. The fork 89 is driven positively towards the front by abutment of the shoulder 96 against the collar 46 and is also driven in this direction by the springs 94. The damper 97 and '99-102 is inoperative during this forward stroke, for the reasons explained above (separation of the pistons 99 and 100, absence of positive coupling between the rod 101 and the abutment 102). On the contrary, however, the dampers 51 and 52 brake the recoil as well as the return to firing position of the unit f-ormed by the sleeve 15 and the barrel 16.

Such a fire-arm has numerous and real advantages, in particular:

A reduced cumbersomeness, since the two feed mechanisms 9 are disposed on parts of the breech mechanism that are narrowed to a substantially rectangular crosssection;

A simple putting out of action yof the retracted feed mechanism, since it depends only on the position of this feed mechanism;

A gain of energy in the driving of the feed mechanism into its firing position since the only members in motion are those which transmit directly the recoil energy to this feed mechanism;

A great facility of dismantling of the tire-arm due to the construction of the nut 50;

A great safety of operation due tothe fact tha-t all the moving mem-bers are housed inside a fluid-tight breechcase.

Although the invention has been described with particular reference to a preferred embodiment, it should be understood that the invention is not limited thereto, and that various modifications and changes are possible without departing from the spirit and scope of the invention.

I claim:

1. In a firearm of the type having a breech mechanism movable in a breechcase alon-g a breech mechanism path at least between a loading position and a firing position, means for mounting first and second cartridge feed mechanisms on opposite sides of the breechcase such that either one may be placed in operative firing position to advance cartridges to the breech mechanism path while the other feed mechanism is out of operative tiring position, each feed mechanism comprising a cartridge advancement mechanism positioned to advance cartridges in its respective feed mechanism, said cartridge advancement mechanism being movable with its feed mechanism into and out of the operative firing position such that the cartridge advancement mechanism remains in a position ready to advance cartridges when actuated, whether its feed mechanism is in or out of its operative ring position, each feed mechanism further including a drive means, also movable with its feed mechanism in and out of its operative firing position, for actuating said cartridge advancement mechanism, a single motor member connected in said .firearm for longitudinal movement along an actuating path after a cartridge has been tired, the said motor member being movable along the same said actuating path regardless of which one of the first and second feed mechanisms is in the operative firing position, said motor member being positioned to directly engage only the drive means of the one of said :rst and second feed mechanisms which is in the operative tiring position to operate the same and hence operate its cartridge. advancement mechanism when the said motor member moves along the said actuating path.

2. A tire-arm according to claim 1 wherein the motor member is in the form of a fork having a. base portion located at the forward end of the fork and a pair of branches connected to and located rearwardly of the said base portion, the rearward part of each branch being positioned to operate one of said feed mechanisms when its respective feed mechanism is in the operative ring position.

3. A lire-arm according to claim 2 wherein said breechcase includes a front part having a cylindrical interior surface, a sleeve mounted in said frorit part and having a barrel attached thereto, the barrel and the sleeve forming a re-coiling part of the fire-arm, an annular space being provided between the sleeve and the said front part, said fork being located in said annular 12 space, the base portion of the fork being guided by a collar attached to the sleeve, and the branches being guided by a member fixed with respect to the breech case.

4. A tire-arm according to claim 3 wherein at least one compression spring is mounted to act between the fork and the collar for urging the fork to re-coil with respect to the breechcase, and including an abutment means for returning thefork to its forward position during the forward return of the said re-coiling part of the fire-arm. l

5. A tire-arm according to claim 4 wherein the interior of the said base portion of the fork is in the form .of a cylinder which forms a part of a dash-pot means for regulating the re-coil speed of the fork.

6. A tire-arm according to claim 5 wherein each feed mechanism includes a casing part directly connected to the breechcase and a cover connected to the said casing par and wherein said drive means of each feed mechanism includes a motion transmission mechanism which is housed in said casing part and wherein said cartridge advancement mechanism of each feed mechanism is also housed in the said cover, such that the said motion transmitting mechanism and the said cartridge advancement mechanism are capable of being separated from each other for the transverse introduction of a cartridge belt.

7. A fire-arm according to claim 1 wherein the rear of the motor member, in its rest position, is located forward of the front face of the feed mechanisms in a manner to permit the transverse movement into firing position of either one of the feed mechanisms.

References Cited UNITED STATES PATENTS 3,455,204 7/1969 Stoner 89-33.2

B-ENIAMI-N A. BORCH'ELT, Primary Examiner S. C. BENTLEY, Assistant Examiner U.S. Cl. X.R. 89-33 C l 

